Factors Affecting Outcomes in Patients With Stage III & IV Squamous Cell Carcinoma of Oropharynx: The Importance of p16 Status, BMI, and Race

Objective To identify racial disparities in survival outcomes among Stage III & IV patients with squamous cell carcinomas (SCCa) of the oropharynx treated with definitive radiation therapy (RT), with concurrent chemotherapy. Method This is a retrospective analysis of patients with stage III & IV SCCa of oropharynx treated with definitive RT at the State Academic Medical Center. All patients were treated to 70 Gy utilizing intensity-modulated radiation treatment (IMRT), and received concurrent chemotherapy with weekly cisplatin or cetuximab. Chi-square test was used to test the goodness of fit, overall survival (OS), and locoregional control (LRC) comparing races were generated by using Log-rank test & Kaplan-Meier method. The covariables associated with the OS and LRC were determined by the Cox regression model. A p-value of less than 0.05 was considered statistically significant. The SPSS 24.0 software (IBM Corp., Armonk, NY) was used. Results In the total 73 eligible patients, 54.8% were black, and 45.2% white patients. Stage distribution (per American Joint Committee on Cancer-AJCC 8th Ed) between black patients vs. white patients, Stage III (45.5% vs. 54.5%) and for Stage IV (56.5% vs. 43.5%); p=0.499. Median follow-up for the entire group was 41 months (range: 4-144 months). In the univariate analysis, variables p16 status, body mass index (BMI), alcohol history and tumor subsite were found to be significant. In the multivariate analysis, only BMI has shown to be significant. Three-year LRC for black patients was 37.8% vs. 66.8% in white patients (p=0.354) and three-year OS for black patients was 51.8% vs. 80.9% for white patients (p=0.063), respectively. Five-year OS for p16 positive patients was 69.7% vs. 43% for p16 negative patients (p=0.034). Five-year OS for Stage IV black patients was 34% vs. 69.5% for Stage IV white patients (p=0.014). Conclusion Among all the co-variables examined, only BMI has shown affecting the OS outcomes; gender and BMI shown to be affecting the LRC. Racial factor appears to be significant in Stage IV patients.